Gerbil’s are rodents in the subfamily Gerbillinae. About 110 species exist in 14 genera, but the Mongolian gerbil is the most common choice as a pet. The Mongolian gerbil is native to Asia and was brought to the United States in 1954 for research purposes. They were being sold as pets by 1964, although it is illegal to own them in California. Here’s how to keep a pet gerbil.